Hi Daniel,
I have built three Whitleys, two were Ex-Frog (Novo Kits made in Russia from the old Frog moulds.) The moulds have suffered over time but are still quite acceptable. The last one I bought was an original Frog kit :very nice.
There is an excellent Plastic Kit Show in Huddersfield, West Yorkshire on the 8th of Feb.2004. Lots of exhibits and HUNDREDS of unbuilts.
You're sure to find what you want there and the prices are usually very reasonable.
Good luck,
Peter